Sugababes @ IndigO2, September 14

It feels like crunch time for Sugababes. The pop trio's most charismatic member, the spiky, snarl-faced Mutya Buena, jumped ship in 2005; last year's greatest hits compilation became the band's lowest seller since their debut, and their Comic Relief collaboration with Girls Aloud, a cartoony cover of Aerosmith's 'Walk This Way', seemed a tad down-market for the group who gave us 'Freak Like Me' and 'Push The Button'.

But tonight’s gig, essentially a live launch for new single 'About You Now', isn’t marred by any what-will-become-of-us jitters. The girls strut on stage looking poised, polished and – with their heavily-flared trousers and over-sized belts – rather like a noughties version of Brotherhood of Man. Backed by a forceful five-piece band, the girls’ energy belies their slightly sexless appearance: a rocked-up rendition of 'Round Round' is combined with some nifty mike-twiddling choreography; 'In The Middle' is as barnstorming as a 30-stone pig-on-speed and 'Freak Like Me' still sounds like the soundtrack to a thousand convent girls going off the rails.

Vocally, the girls are on sparkling form. Their harmonies on ‘Too Lost In You’ manage the unfathomable trick of sounding both delicate and sturdy, while an acoustic version of 'Ugly' proves that no member's a slacker in the trilling department. Only a flaccid, dad-pleasing rendition of Primal Scream's 'Rocks' falls flat, exposing the fact that Sugababes - sleek and soulful as they are - will never be pop’s most dynamic live act.

Avenging tabloid rumours that Amelle Berrabah is on the verge of leaving, the girls seem cheerful, comfortable in each others' presence and excited to be on stage. If anything, the sassy, gravel-throated Berrabah is threatening to dethrone Buchanan, the group’s sole original member, as Queen Babe; she certainly matches her for vocal acrobatics at the end of 'Red Dress', one of the night's pulsating highlights.

Most impressively, three new songs from Sugababes' forthcoming fifth album – the wryly-titled Change - more than hold their own alongside the group’s nugget-packed back catalogue. 'Denial' rides its elastic bassline to a transcendent, melodically-inspired chorus, while new single 'About You Know' is as sweet and fizzy as a shaken-up bottle of Coke. These Babes, it seems, haven't run out of pop sugar just yet.